Audi also underscores its prowess in the field of lighting technology. The brand already offers LED headlights in many model series. The new technologies that Audi is developing for the future boast a high degree of intelligence and are controlled entirely electronically.
Today’s lighting technologies
Audi has been the key driver of progress in lighting technology for many years – from LED daytime driving lights to the LED headlights available in many model series today. As pronounced design features, the headlights dominate the appearance of the Audi models. Due to their good road surface illumination, they also make a substantial contribution to active safety. Technologies such as Audi adaptive light already react to the vehicle’s surroundings and to other road users.
Audi adaptive light
Audi adaptive light for the xenon headlights is available in a number of different configurations. Its control unit governs the swiveling xenon modules to ensure that they always provide the ideal illumination for urban, country and highway applications. The driver can set the swivel characteristics via the Audi drive select driving dynamics system. The all-weather light – which is integrated into the main headlights – replaces the fog lights – with a higher range, wider verge illumination and lower backglare.
The variable headlight range control is an especially attractive component for the adaptive light. A video camera recognizes preceding and approaching vehicles by their lights. The control unit adapts the range of the vehicle’s own light accordingly – through a smooth range that always provides the maximum possible illumination.
A technological breakthrough from Audi is the networking of the headlight control unit with the MMI navigation . The navigation system reads the route data in advance and relays them to the light computer, so as to activate the longer-range highway lighting while still on the on-ramp to the highway, for example. The system automatically switches on the cornering lights before entering an intersection; in countries like the United Kingdom, it automatically switches the headlights from driving on the right to driving on the left.
LED daytime running lights and LED rear lights
Having made their first appearance in 2004 on an Audi A8 W12, white LED daytime running lights are now available for every model in various configurations. The Audi A1, for example, uses two light-emitting diodes per headlight. The LED’s light shines into a transparent polymer tube called a light guide to produce a homogenous contour. In the A7 Sportback, the daytime running lights of the optional LED headlights are also linear, but comprise 18 individual LEDs behind a polymer body.
Rear lights using LED technology are available either as standard or as an option for all Audi models. They produce a distinctive light pattern that in many cases also produces three-dimensional effects. The light-emitting diodes reach their full light intensity almost instantaneously – if the driver has to brake suddenly, the driver behind gains valuable fractions of a second.
Indicator light with dynamic display
When revamping its high-performance sports car, the R8, Audi recently brought the indicator light with dynamic display to series production. It sends clear signals to its surroundings – unlike today’s indicators.
The wipe-action indicator controls the LEDs sequentially in blocks in the turning direction, from the inside to the outside edge of the vehicle. Other road users benefit from the clearer indicator direction.
The function is provided by 30 LEDs arranged linearly, which are driven successively in seven segments at an interval of 150 milliseconds. The advantages: additional direction information, more intuitive indicator signal and more road safety.
Audi has consistently been setting milestones in the field of LED headlights. Since the market launch on the high-performance sports car, the Audi R8, the brand with the four rings has managed to consistently extend its lead – they are even available in the new A3 model series.
With a color temperature of 5,500 Kelvin, the light from LEDs resembles daylight and is therefore much less tiring for the eyes. The light-emitting diodes are virtually maintenance-free and designed for the life of the vehicle. They also score points in efficiency with their low power consumption. The low beams, for example, consume only around 40 watts per unit, five percent less than the already highly efficient xenon headlights.
The innovative technology of the LED headlights has led to a radically new design. On the Audi A8, for instance, the low beams comprise ten individual lens modules extending through the headlight in a distinctive arc below the chrome contour known as the wing, on account of its shape. Directly below this is another arc of 22 white and 22 yellow LEDs for the daytime running lights and the indicators. Their thick wall technology makes them appear to the onlooker as homogeneous, continuous strips of light.
The high-beam headlight is housed above the wing. Its light is generated by two powerful four-chip LEDs and a free-form reflection system; an assistance function switches between the low and main beams. Additional high-output LEDs generate the highway light and the cornering light. LEDs do not reach especially high temperatures. Red light-emitting diodes withstand about 120 and white ones 150 degrees Celsius – much less than halogen headlights, which generate temperatures of up to 400 degrees Celsius.
Audi’s designers therefore make sure that the LEDs transmit their heat in a targeted manner to the headlight glass by using fans, in order to keep it free of snow in winter and prevent misting over.
Lighting technologies – outlook
Audi is already developing the lighting technologies of tomorrow. Three central themes are emerging: the lighting on tomorrow’s Audi models will react even more intensively to environmental conditions, it will communicate in various ways with its surroundings and in this way will increase active safety still further. The light of the future will be controlled fully electronically and become an even more compelling proposition thanks to new dynamic functions.
Audi Matrix LED headlights
The term Audi Matrix LED headlights is used to describe the headlight technology of the future at Audi. During the last two years the brand has exhibited widely differing visual and technical versions of its technology on a series of show cars.
The “Matrix Beam” principle consists of dividing the LED main-beam headlight up into a large number of individual segments. The small individual diodes backed by lenses or reflectors always provide excellent illumination without needing a swiveling mechanism. They are simply switched on and off individually or dimmed to suit the situation.
The Audi Matrix LED headlights obtain the information they need from a camera, the navigation system or additional sensors. If the camera detects other vehicles, these innovative headlights fade out the appropriate area of the high-beam headlights, which contain various light-source sectors. The headlights can also illuminate the areas between several vehicles in complex situations. Based on navigation data, the high-beam headlight anticipates the bend and swivels to illuminate the road before the driver has even turned the wheel.
The “Matrix Beam” technology provides developers with fascinating opportunities in terms of the number of individual LEDs, their layout and the size and styling of the headlights. This functionality is also reflected in the special headlight styling. The illumination of the segments can also be seen from the outside.
The challenges that need to be mastered relate to the extremely low tolerances permitted during manufacture and assembly of the components, the methods used to energize the headlights and control them independently, along with the overall efficiency of the package, the uniformity of the conical light beam and the airflow path through the headlights. Audi is in a position to answer all these questions, so that the new technology will soon be introduced on production cars.
Laser tail light
The laser tail light is generated by a laser diode and provides drivers behind with a bright, clear signal. In good visibility the fan-shaped laser tail light that shines slightly downward is perceived as a red line on the road and prompts the driver behind to maintain sufficient distance – similar to a stop line.
In fog or spray, the laser beam strikes the water droplets in the air and makes them visible; the line is then seen as a triangle. The laser tail light looks like a large warning triangle.
OLED technology is yet another example of Audi’s pioneering work in the vehicle lighting area. The abbreviation stands for organic light emitting diode. Unlike the LEDs currently in use, which consist of semiconductor crystals, OLEDs are made from an organic material.
The material is spread extremely thinly – the coating is only a few thousandths of a millimeter thick – on an absolutely flat surface such as highly polished display glass. When an electrical voltage is applied, the molecules emit photons and the surface lights up. The light distribution is very homogeneous and very energy-efficient. They are ideally suited for use inside the vehicle or in rear lights.
External light design using OLED technology, which Audi is aiming to adopt, will be as intelligent as it is attractive. It can, for example, react to the approaching driver, follow his or her movements and highlight the main contours of the vehicle or the door handle. When the driver has entered the car, restrained OLED lighting will become active inside.
A scenario in the OLED technology area to which intensive thought has already been devoted is the “swarm”. The Audi engineers have transformed a vehicle’s rear end into a large, continuous light surface, with innumerable small points of light flickering like a swarm of fish.
The movements of the red dots follow the movements of the vehicle. When a right turn is made, they flow to the right; when the car is braked, they flow rapidly forwards; the faster the car goes, the faster they move. The following driver can always see right away what the driver of the car in front is doing.
AMOLED technology / digital rearview mirror
Another variant of OLED technology which Audi is involved in is called AMOLED (active matrix organic light emitting diode). The technology originates from the consumer electronics space. Audi uses the technology for instance in the Audi R18 e-tron quattro; a camera/monitor system replaces the optical rearview mirror in the cockpit of the electrically powered high-performance sports car. The system has already made its compelling premier in the Audi Sport prototypes at the Le Mans 24 Hours.
The high-resolution AMOLED display is mounted on the headlining of the Audi R18 e-tron quattro, which does not have a rear window. It offers a visible screen diagonal of 6.8 inches; each of its 600,000- pixels can be driven individually.
It offers ten times more contrast and consumes around 30 percent less energy than a corresponding LCD monitor; switching times are just a few milliseconds irrespective of the ambient temperature. Including its mechanism the display is just 7 millimeters (0.28 in) thick.
The small, lightweight camera sits on the back of the R18 e-tron quattro under the roof edge; its cover lens is heated to prevent it misting over or freezing. With its extremely high dynamic range of around 130 dB, the camera is roughly on a par with the contrast range of the human eye. It uses a lens with a diameter of just a few millimeters and covers a much larger field of vision than a conventional rearview mirror.
A control unit, which also provides the power supply, calculates the colors and contrast ratios of the data so that the image is always brilliant and detailed. In the dark the control unit prevents the headlights of other cars from dazzling the driver.
[Source: Audi AG]